Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
Issued by NWS New Orleans/Baton Rouge, LA
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766 FXUS64 KLIX 111938 AFDLIX Area Forecast Discussion National Weather Service New Orleans LA 238 PM CDT Sat May 11 2024 ...New SHORT TERM, LONG TERM, MARINE... .SHORT TERM... (This evening through Sunday night) Issued at 209 PM CDT Sat May 11 2024 Tonight through Sunday evening, zonal flow will dominate the upper level pattern. Surface winds will shift from northerly to southerly overnight tonight, which will help to reintroduce moisture into the area. This will also help increase instability somewhat. Conditions, looking at the models, will be fairly dry tonight through tomorrow night, but an isolated shower or two is possible for our northern areas tomorrow morning. A weak upper level impulse will influence the area Sunday night through Monday morning (beginning of the long term forecast). Southerly surface winds will continue to advect humid and moist air into the area, increasing instability. Scattered showers and storms are possible Sunday night into Monday morning. These look mostly fairly weak overall and stratiform, but there are a lot of uncertainties in the models regarding timing of the impulse and beginning of the rain. Some localized flash flooding concerns will be possible early Monday, but not as likely as later in the daytime on Monday (which is covered in the long term forecast). MSW && .LONG TERM... (Monday through Friday night) Issued at 209 PM CDT Sat May 11 2024 By Monday morning, upper ridging will move to the eastern Gulf near Florida. The surface and mid level cyclone will be over Kansas with moderate southerly flow across the local area. While there will be a break between warm advection precipitation Sunday night into Monday, the airmass is expected to destabilize again with precipitable water values returning to around 2 inches overnight. Instability and shear would be sufficient for a severe weather threat, with details depending on the evolution of events Sunday night into Monday. Heavy rain will also be a significant threat with current forecasts of 2-3 inches across a large portion of the CWA from late Monday afternoon through Tuesday morning. Once the upper system and surface front progress to the east of the area during the first half of Tuesday, there will be probably a 36 to 48 hour period of quiet weather until the next trough approaches from the west. Precipitable water values will remain below an inch for much of the period from midday Tuesday to midday Thursday. Precipitable water values then increase to near 2 inches again with plenty of instability available for thunderstorms. The current global model solutions hold most of the heavy rainfall to the north of our CWA, but considering this is 6 days out, don`t feel comfortable lowering any messaging regarding a wet pattern at this time. Interaction, or lack of, between northern and southern stream shortwaves could produce significantly different results as there are large differences even between the 50th and 90th NBM percentile QPF values, as much as 2-3 inches for Thursday into Friday. Beyond Friday, global solutions fall out of any significant agreement, as the GFS drags a southern stream shortwave across the area next weekend, while the ECMWF solution is dry. With some uncertainty in timing of systems during the extended period, will stick to the NBM deterministic numbers for temperatures. RW && .AVIATION... (18Z TAFS) Issued at 1205 PM CDT Sat May 11 2024 VFR conditions prevail at all area airports and will persist through the forecast period. Wind shifts greater than 30 degrees will be expected at all area airports throughout the forecast period. MSW && .MARINE... Issued at 209 PM CDT Sat May 11 2024 Marine conditions will remain calm/benign through tomorrow afternoon. A system will be moving through the area Sunday night through Tuesday morning, which will cause strong (15-25kts) southerly winds and higher seas through Wednesday morning. Winds will ease shift northerly Wednesday into early Thursday behind the system. Another system will likely move through the area Thursday through Saturday morning, which will strengthen the southerly winds (15-25kts) and bring higher seas. MSW && .PRELIMINARY POINT TEMPS/POPS... MCB 61 78 64 83 / 10 40 70 90 BTR 67 85 72 88 / 20 40 60 70 ASD 66 85 70 86 / 10 20 60 80 MSY 71 85 74 86 / 20 20 60 70 GPT 67 83 71 84 / 10 10 60 90 PQL 63 85 69 85 / 10 10 50 90 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...None. MS...None. GM...None. && $$ SHORT TERM...MSW LONG TERM....RW AVIATION...MSW MARINE...MSW